[01/19] drm/fourcc: Add a function to tell if the format embeds alpha

Message ID b58c65b26e59dff7917d90846cb797a11ca09efa.1515494838.git-series.maxime.ripard@free-electrons.com
State New
Headers show
Series
  • drm/sun4i: Support more planes, zpos and plane-wide alpha
Related show

Commit Message

Maxime Ripard Jan. 9, 2018, 10:56 a.m.
There's a bunch of drivers that duplicate the same function to know if a
particular format embeds an alpha component or not.

Let's create a helper to avoid duplicating that logic.

Cc: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: Eric Anholt <eric@anholt.net>
Cc: Inki Dae <inki.dae@samsung.com>
Cc: Joonyoung Shim <jy0922.shim@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Mark Yao <mark.yao@rock-chips.com>
Cc: Seung-Woo Kim <sw0312.kim@samsung.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
 drivers/gpu/drm/drm_fourcc.c | 43 +++++++++++++++++++++++++++++++++++++-
 include/drm/drm_fourcc.h     |  1 +-
 2 files changed, 44 insertions(+)

Comments

Laurent Pinchart Jan. 9, 2018, 12:29 p.m. | #1
Hi Maxime,

Thank you for the patch.

On Tuesday, 9 January 2018 12:56:20 EET Maxime Ripard wrote:
> There's a bunch of drivers that duplicate the same function to know if a
> particular format embeds an alpha component or not.
> 
> Let's create a helper to avoid duplicating that logic.
> 
> Cc: Boris Brezillon <boris.brezillon@free-electrons.com>
> Cc: Eric Anholt <eric@anholt.net>
> Cc: Inki Dae <inki.dae@samsung.com>
> Cc: Joonyoung Shim <jy0922.shim@samsung.com>
> Cc: Kyungmin Park <kyungmin.park@samsung.com>
> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Cc: Mark Yao <mark.yao@rock-chips.com>
> Cc: Seung-Woo Kim <sw0312.kim@samsung.com>
> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> ---
>  drivers/gpu/drm/drm_fourcc.c | 43 +++++++++++++++++++++++++++++++++++++-
>  include/drm/drm_fourcc.h     |  1 +-
>  2 files changed, 44 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c
> index 9c0152df45ad..6e6227d6a46b 100644
> --- a/drivers/gpu/drm/drm_fourcc.c
> +++ b/drivers/gpu/drm/drm_fourcc.c
> @@ -348,3 +348,46 @@ int drm_format_plane_height(int height, uint32_t
> format, int plane) return height / info->vsub;
>  }
>  EXPORT_SYMBOL(drm_format_plane_height);
> +
> +/**
> + * drm_format_has_alpha - get whether the format embeds an alpha component
> + * @format: pixel format (DRM_FORMAT_*)
> + *
> + * Returns:
> + * true if the format embeds an alpha component, false otherwise.
> + */
> +bool drm_format_has_alpha(uint32_t format)
> +{
> +	switch (format) {
> +	case DRM_FORMAT_ARGB4444:
> +	case DRM_FORMAT_ABGR4444:
> +	case DRM_FORMAT_RGBA4444:
> +	case DRM_FORMAT_BGRA4444:
> +	case DRM_FORMAT_ARGB1555:
> +	case DRM_FORMAT_ABGR1555:
> +	case DRM_FORMAT_RGBA5551:
> +	case DRM_FORMAT_BGRA5551:
> +	case DRM_FORMAT_ARGB8888:
> +	case DRM_FORMAT_ABGR8888:
> +	case DRM_FORMAT_RGBA8888:
> +	case DRM_FORMAT_BGRA8888:
> +	case DRM_FORMAT_ARGB2101010:
> +	case DRM_FORMAT_ABGR2101010:
> +	case DRM_FORMAT_RGBA1010102:
> +	case DRM_FORMAT_BGRA1010102:
> +	case DRM_FORMAT_AYUV:
> +	case DRM_FORMAT_XRGB8888_A8:
> +	case DRM_FORMAT_XBGR8888_A8:
> +	case DRM_FORMAT_RGBX8888_A8:
> +	case DRM_FORMAT_BGRX8888_A8:
> +	case DRM_FORMAT_RGB888_A8:
> +	case DRM_FORMAT_BGR888_A8:
> +	case DRM_FORMAT_RGB565_A8:
> +	case DRM_FORMAT_BGR565_A8:
> +		return true;
> +
> +	default:
> +		return false;
> +	}
> +}
> +EXPORT_SYMBOL(drm_format_has_alpha);

How about adding the information to struct drm_format_info instead ? 
drm_format_has_alpha() could then be implemented as

bool drm_format_has_alpha(uint32_t format)
{
	const struct drm_format_info *info;

	info = drm_format_info(format);
	return info ? info->has_alpha : false;
}

although drivers should really use the drm_framebuffer::format field directly 
in most cases, so the helper might not be needed at all.

> diff --git a/include/drm/drm_fourcc.h b/include/drm/drm_fourcc.h
> index 6942e84b6edd..e08fc22c5f78 100644
> --- a/include/drm/drm_fourcc.h
> +++ b/include/drm/drm_fourcc.h
> @@ -69,5 +69,6 @@ int drm_format_vert_chroma_subsampling(uint32_t format);
>  int drm_format_plane_width(int width, uint32_t format, int plane);
>  int drm_format_plane_height(int height, uint32_t format, int plane);
>  const char *drm_get_format_name(uint32_t format, struct drm_format_name_buf
> *buf);
> +bool drm_format_has_alpha(uint32_t format);
> 
>  #endif /* __DRM_FOURCC_H__ */
Ayan Halder Jan. 15, 2018, 3:47 p.m. | #2
On Tue, Jan 09, 2018 at 02:28:33PM +0100, Maxime Ripard wrote:
> Hi Laurent,
>
> On Tue, Jan 09, 2018 at 02:29:58PM +0200, Laurent Pinchart wrote:
> > On Tuesday, 9 January 2018 12:56:20 EET Maxime Ripard wrote:
> > > There's a bunch of drivers that duplicate the same function to know if a
> > > particular format embeds an alpha component or not.
> > >
> > > Let's create a helper to avoid duplicating that logic.
> > >
> > > Cc: Boris Brezillon <boris.brezillon@free-electrons.com>
> > > Cc: Eric Anholt <eric@anholt.net>
> > > Cc: Inki Dae <inki.dae@samsung.com>
> > > Cc: Joonyoung Shim <jy0922.shim@samsung.com>
> > > Cc: Kyungmin Park <kyungmin.park@samsung.com>
> > > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > > Cc: Mark Yao <mark.yao@rock-chips.com>
> > > Cc: Seung-Woo Kim <sw0312.kim@samsung.com>
> > > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> > > ---
> > >  drivers/gpu/drm/drm_fourcc.c | 43 +++++++++++++++++++++++++++++++++++++-
> > >  include/drm/drm_fourcc.h     |  1 +-
> > >  2 files changed, 44 insertions(+)
> > >
> > > diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c
> > > index 9c0152df45ad..6e6227d6a46b 100644
> > > --- a/drivers/gpu/drm/drm_fourcc.c
> > > +++ b/drivers/gpu/drm/drm_fourcc.c
> > > @@ -348,3 +348,46 @@ int drm_format_plane_height(int height, uint32_t
> > > format, int plane) return height / info->vsub;
> > >  }
> > >  EXPORT_SYMBOL(drm_format_plane_height);
> > > +
> > > +/**
> > > + * drm_format_has_alpha - get whether the format embeds an alpha component
> > > + * @format: pixel format (DRM_FORMAT_*)
> > > + *
> > > + * Returns:
> > > + * true if the format embeds an alpha component, false otherwise.
> > > + */
> > > +bool drm_format_has_alpha(uint32_t format)
> > > +{
> > > + switch (format) {
> > > + case DRM_FORMAT_ARGB4444:
> > > + case DRM_FORMAT_ABGR4444:
> > > + case DRM_FORMAT_RGBA4444:
> > > + case DRM_FORMAT_BGRA4444:
> > > + case DRM_FORMAT_ARGB1555:
> > > + case DRM_FORMAT_ABGR1555:
> > > + case DRM_FORMAT_RGBA5551:
> > > + case DRM_FORMAT_BGRA5551:
> > > + case DRM_FORMAT_ARGB8888:
> > > + case DRM_FORMAT_ABGR8888:
> > > + case DRM_FORMAT_RGBA8888:
> > > + case DRM_FORMAT_BGRA8888:
> > > + case DRM_FORMAT_ARGB2101010:
> > > + case DRM_FORMAT_ABGR2101010:
> > > + case DRM_FORMAT_RGBA1010102:
> > > + case DRM_FORMAT_BGRA1010102:
> > > + case DRM_FORMAT_AYUV:
> > > + case DRM_FORMAT_XRGB8888_A8:
> > > + case DRM_FORMAT_XBGR8888_A8:
> > > + case DRM_FORMAT_RGBX8888_A8:
> > > + case DRM_FORMAT_BGRX8888_A8:
> > > + case DRM_FORMAT_RGB888_A8:
> > > + case DRM_FORMAT_BGR888_A8:
> > > + case DRM_FORMAT_RGB565_A8:
> > > + case DRM_FORMAT_BGR565_A8:
> > > +         return true;
> > > +
> > > + default:
> > > +         return false;
> > > + }
> > > +}
> > > +EXPORT_SYMBOL(drm_format_has_alpha);
> >
> > How about adding the information to struct drm_format_info instead ?
> > drm_format_has_alpha() could then be implemented as
> >
> > bool drm_format_has_alpha(uint32_t format)
> > {
> >     const struct drm_format_info *info;
> >
> >     info = drm_format_info(format);
> >     return info ? info->has_alpha : false;
> > }
>
> I considered it, and wasn't too sure about if adding more fields to
> drm_format_info was ok. I can definitely do it that way.
Are you going to send an updated patch with the change mentioned here.
Or should I update my patch (https://patchwork.kernel.org/patch/10161023/)
and change the type of '.alpha' to boolean to denote if the color
format has an alpha channel or not.

> > although drivers should really use the drm_framebuffer::format field directly
> > in most cases, so the helper might not be needed at all.
>
> The drivers converted in my serie shouldn't be too hard to convert to
> use drm_format_info directly, so that can be removed as well.
>
> Maxime
>
> --
> Maxime Ripard, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com



> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

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Ayan Halder Jan. 16, 2018, 10:37 a.m. | #3
On Tue, Jan 09, 2018 at 02:28:33PM +0100, Maxime Ripard wrote:
> Hi Laurent,
> 
> On Tue, Jan 09, 2018 at 02:29:58PM +0200, Laurent Pinchart wrote:
> > On Tuesday, 9 January 2018 12:56:20 EET Maxime Ripard wrote:
> > > There's a bunch of drivers that duplicate the same function to know if a
> > > particular format embeds an alpha component or not.
> > > 
> > > Let's create a helper to avoid duplicating that logic.
> > > 
> > > Cc: Boris Brezillon <boris.brezillon@free-electrons.com>
> > > Cc: Eric Anholt <eric@anholt.net>
> > > Cc: Inki Dae <inki.dae@samsung.com>
> > > Cc: Joonyoung Shim <jy0922.shim@samsung.com>
> > > Cc: Kyungmin Park <kyungmin.park@samsung.com>
> > > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > > Cc: Mark Yao <mark.yao@rock-chips.com>
> > > Cc: Seung-Woo Kim <sw0312.kim@samsung.com>
> > > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> > > ---
> > >  drivers/gpu/drm/drm_fourcc.c | 43 +++++++++++++++++++++++++++++++++++++-
> > >  include/drm/drm_fourcc.h     |  1 +-
> > >  2 files changed, 44 insertions(+)
> > > 
> > > diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c
> > > index 9c0152df45ad..6e6227d6a46b 100644
> > > --- a/drivers/gpu/drm/drm_fourcc.c
> > > +++ b/drivers/gpu/drm/drm_fourcc.c
> > > @@ -348,3 +348,46 @@ int drm_format_plane_height(int height, uint32_t
> > > format, int plane) return height / info->vsub;
> > >  }
> > >  EXPORT_SYMBOL(drm_format_plane_height);
> > > +
> > > +/**
> > > + * drm_format_has_alpha - get whether the format embeds an alpha component
> > > + * @format: pixel format (DRM_FORMAT_*)
> > > + *
> > > + * Returns:
> > > + * true if the format embeds an alpha component, false otherwise.
> > > + */
> > > +bool drm_format_has_alpha(uint32_t format)
> > > +{
> > > +	switch (format) {
> > > +	case DRM_FORMAT_ARGB4444:
> > > +	case DRM_FORMAT_ABGR4444:
> > > +	case DRM_FORMAT_RGBA4444:
> > > +	case DRM_FORMAT_BGRA4444:
> > > +	case DRM_FORMAT_ARGB1555:
> > > +	case DRM_FORMAT_ABGR1555:
> > > +	case DRM_FORMAT_RGBA5551:
> > > +	case DRM_FORMAT_BGRA5551:
> > > +	case DRM_FORMAT_ARGB8888:
> > > +	case DRM_FORMAT_ABGR8888:
> > > +	case DRM_FORMAT_RGBA8888:
> > > +	case DRM_FORMAT_BGRA8888:
> > > +	case DRM_FORMAT_ARGB2101010:
> > > +	case DRM_FORMAT_ABGR2101010:
> > > +	case DRM_FORMAT_RGBA1010102:
> > > +	case DRM_FORMAT_BGRA1010102:
> > > +	case DRM_FORMAT_AYUV:
> > > +	case DRM_FORMAT_XRGB8888_A8:
> > > +	case DRM_FORMAT_XBGR8888_A8:
> > > +	case DRM_FORMAT_RGBX8888_A8:
> > > +	case DRM_FORMAT_BGRX8888_A8:
> > > +	case DRM_FORMAT_RGB888_A8:
> > > +	case DRM_FORMAT_BGR888_A8:
> > > +	case DRM_FORMAT_RGB565_A8:
> > > +	case DRM_FORMAT_BGR565_A8:
> > > +		return true;
> > > +
> > > +	default:
> > > +		return false;
> > > +	}
> > > +}
> > > +EXPORT_SYMBOL(drm_format_has_alpha);
> > 
> > How about adding the information to struct drm_format_info instead ? 
> > drm_format_has_alpha() could then be implemented as
> > 
> > bool drm_format_has_alpha(uint32_t format)
> > {
> > 	const struct drm_format_info *info;
> > 
> > 	info = drm_format_info(format);
> > 	return info ? info->has_alpha : false;
> > }
> 
> I considered it, and wasn't too sure about if adding more fields to
> drm_format_info was ok. I can definitely do it that way.\
Are you going to send an updated patch with the change mentioned here.
Or should I update my patch (https://patchwork.kernel.org/patch/10161023/)
and change the type of '.alpha' to boolean to denote if the color
format has an alpha channel or not.
> 
> > although drivers should really use the drm_framebuffer::format field directly 
> > in most cases, so the helper might not be needed at all.
> 
> The drivers converted in my serie shouldn't be too hard to convert to
> use drm_format_info directly, so that can be removed as well.
> 
> Maxime
> 
> -- 
> Maxime Ripard, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com



> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
Ayan Halder Jan. 17, 2018, 5:55 p.m. | #4
On Tue, Jan 16, 2018 at 09:17:24PM +0100, Maxime Ripard wrote:
> Hi Ayan,
> 
> On Mon, Jan 15, 2018 at 03:47:44PM +0000, Ayan Halder wrote:
> > On Tue, Jan 09, 2018 at 02:28:33PM +0100, Maxime Ripard wrote:
> > > On Tue, Jan 09, 2018 at 02:29:58PM +0200, Laurent Pinchart wrote:
> > > > On Tuesday, 9 January 2018 12:56:20 EET Maxime Ripard wrote:
> > > > > There's a bunch of drivers that duplicate the same function to know if a
> > > > > particular format embeds an alpha component or not.
> > > > >
> > > > > Let's create a helper to avoid duplicating that logic.
> > > > >
> > > > > Cc: Boris Brezillon <boris.brezillon@free-electrons.com>
> > > > > Cc: Eric Anholt <eric@anholt.net>
> > > > > Cc: Inki Dae <inki.dae@samsung.com>
> > > > > Cc: Joonyoung Shim <jy0922.shim@samsung.com>
> > > > > Cc: Kyungmin Park <kyungmin.park@samsung.com>
> > > > > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > > > > Cc: Mark Yao <mark.yao@rock-chips.com>
> > > > > Cc: Seung-Woo Kim <sw0312.kim@samsung.com>
> > > > > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> > > > > ---
> > > > >  drivers/gpu/drm/drm_fourcc.c | 43 +++++++++++++++++++++++++++++++++++++-
> > > > >  include/drm/drm_fourcc.h     |  1 +-
> > > > >  2 files changed, 44 insertions(+)
> > > > >
> > > > > diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c
> > > > > index 9c0152df45ad..6e6227d6a46b 100644
> > > > > --- a/drivers/gpu/drm/drm_fourcc.c
> > > > > +++ b/drivers/gpu/drm/drm_fourcc.c
> > > > > @@ -348,3 +348,46 @@ int drm_format_plane_height(int height, uint32_t
> > > > > format, int plane) return height / info->vsub;
> > > > >  }
> > > > >  EXPORT_SYMBOL(drm_format_plane_height);
> > > > > +
> > > > > +/**
> > > > > + * drm_format_has_alpha - get whether the format embeds an alpha component
> > > > > + * @format: pixel format (DRM_FORMAT_*)
> > > > > + *
> > > > > + * Returns:
> > > > > + * true if the format embeds an alpha component, false otherwise.
> > > > > + */
> > > > > +bool drm_format_has_alpha(uint32_t format)
> > > > > +{
> > > > > + switch (format) {
> > > > > + case DRM_FORMAT_ARGB4444:
> > > > > + case DRM_FORMAT_ABGR4444:
> > > > > + case DRM_FORMAT_RGBA4444:
> > > > > + case DRM_FORMAT_BGRA4444:
> > > > > + case DRM_FORMAT_ARGB1555:
> > > > > + case DRM_FORMAT_ABGR1555:
> > > > > + case DRM_FORMAT_RGBA5551:
> > > > > + case DRM_FORMAT_BGRA5551:
> > > > > + case DRM_FORMAT_ARGB8888:
> > > > > + case DRM_FORMAT_ABGR8888:
> > > > > + case DRM_FORMAT_RGBA8888:
> > > > > + case DRM_FORMAT_BGRA8888:
> > > > > + case DRM_FORMAT_ARGB2101010:
> > > > > + case DRM_FORMAT_ABGR2101010:
> > > > > + case DRM_FORMAT_RGBA1010102:
> > > > > + case DRM_FORMAT_BGRA1010102:
> > > > > + case DRM_FORMAT_AYUV:
> > > > > + case DRM_FORMAT_XRGB8888_A8:
> > > > > + case DRM_FORMAT_XBGR8888_A8:
> > > > > + case DRM_FORMAT_RGBX8888_A8:
> > > > > + case DRM_FORMAT_BGRX8888_A8:
> > > > > + case DRM_FORMAT_RGB888_A8:
> > > > > + case DRM_FORMAT_BGR888_A8:
> > > > > + case DRM_FORMAT_RGB565_A8:
> > > > > + case DRM_FORMAT_BGR565_A8:
> > > > > +         return true;
> > > > > +
> > > > > + default:
> > > > > +         return false;
> > > > > + }
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_format_has_alpha);
> > > >
> > > > How about adding the information to struct drm_format_info instead ?
> > > > drm_format_has_alpha() could then be implemented as
> > > >
> > > > bool drm_format_has_alpha(uint32_t format)
> > > > {
> > > >     const struct drm_format_info *info;
> > > >
> > > >     info = drm_format_info(format);
> > > >     return info ? info->has_alpha : false;
> > > > }
> > >
> > > I considered it, and wasn't too sure about if adding more fields to
> > > drm_format_info was ok. I can definitely do it that way.
> >
> > Are you going to send an updated patch with the change mentioned here.
> > Or should I update my patch (https://patchwork.kernel.org/patch/10161023/)
> > and change the type of '.alpha' to boolean to denote if the color
> > format has an alpha channel or not.
> 
> Yes, I already had those patches ready. I'm just waiting for the
> discussion on the alpha property to settle before sending a v2.
>
Thanks for your response. I will hold on my changes
(https://patchwork.kernel.org/patch/10161339/) as it depends on your patch. 
> Maxime
> 
> -- 
> Maxime Ripard, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com

Patch

diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c
index 9c0152df45ad..6e6227d6a46b 100644
--- a/drivers/gpu/drm/drm_fourcc.c
+++ b/drivers/gpu/drm/drm_fourcc.c
@@ -348,3 +348,46 @@  int drm_format_plane_height(int height, uint32_t format, int plane)
 	return height / info->vsub;
 }
 EXPORT_SYMBOL(drm_format_plane_height);
+
+/**
+ * drm_format_has_alpha - get whether the format embeds an alpha component
+ * @format: pixel format (DRM_FORMAT_*)
+ *
+ * Returns:
+ * true if the format embeds an alpha component, false otherwise.
+ */
+bool drm_format_has_alpha(uint32_t format)
+{
+	switch (format) {
+	case DRM_FORMAT_ARGB4444:
+	case DRM_FORMAT_ABGR4444:
+	case DRM_FORMAT_RGBA4444:
+	case DRM_FORMAT_BGRA4444:
+	case DRM_FORMAT_ARGB1555:
+	case DRM_FORMAT_ABGR1555:
+	case DRM_FORMAT_RGBA5551:
+	case DRM_FORMAT_BGRA5551:
+	case DRM_FORMAT_ARGB8888:
+	case DRM_FORMAT_ABGR8888:
+	case DRM_FORMAT_RGBA8888:
+	case DRM_FORMAT_BGRA8888:
+	case DRM_FORMAT_ARGB2101010:
+	case DRM_FORMAT_ABGR2101010:
+	case DRM_FORMAT_RGBA1010102:
+	case DRM_FORMAT_BGRA1010102:
+	case DRM_FORMAT_AYUV:
+	case DRM_FORMAT_XRGB8888_A8:
+	case DRM_FORMAT_XBGR8888_A8:
+	case DRM_FORMAT_RGBX8888_A8:
+	case DRM_FORMAT_BGRX8888_A8:
+	case DRM_FORMAT_RGB888_A8:
+	case DRM_FORMAT_BGR888_A8:
+	case DRM_FORMAT_RGB565_A8:
+	case DRM_FORMAT_BGR565_A8:
+		return true;
+
+	default:
+		return false;
+	}
+}
+EXPORT_SYMBOL(drm_format_has_alpha);
diff --git a/include/drm/drm_fourcc.h b/include/drm/drm_fourcc.h
index 6942e84b6edd..e08fc22c5f78 100644
--- a/include/drm/drm_fourcc.h
+++ b/include/drm/drm_fourcc.h
@@ -69,5 +69,6 @@  int drm_format_vert_chroma_subsampling(uint32_t format);
 int drm_format_plane_width(int width, uint32_t format, int plane);
 int drm_format_plane_height(int height, uint32_t format, int plane);
 const char *drm_get_format_name(uint32_t format, struct drm_format_name_buf *buf);
+bool drm_format_has_alpha(uint32_t format);
 
 #endif /* __DRM_FOURCC_H__ */